This invention pertains to a protective cover for an air filter and for a conduit connecting the air filter to a breathing mask worn by a firefighter or by another wearer in a hazardous environment. The protective cover comprises a fabric shell made from a heat-resistant, flame-resistant fabric, such as an aluminized fabric.
A breathing mask of a type known heretofore is provided with an air filter, which is contained in a canister having an air inlet or air inlets and being connected to the breathing mask via a conduit, such as a flexible, corrugated conduit. The air filter is designed to remove smoke and/or other chemical and/or biological agents. It is convenient herein to regard smoke as comprised of chemical agents. It is known for the breathing mask to be switchable by its wearer between an operating mode wherein the wearer breathes air delivered to the breathing mask by a self-contained breathing apparatus (SCBA) and an operating mode wherein the wearer breathes air delivered to the wearer through the air filter and the conduit.
Typically, as provided with a breathing mask of the type noted above, the air filter is made from a combustible material and the conduit is made from a material, such as a synthetic rubber applied over a fabric matrix, which is susceptible to combustion or to other heat or flame damage. So as to permit such a breathing mask provided with such an air filter and with such a conduit to be worn by a firefighter or by another wearer in a hazardous environment exposing the wearer potentially to heat and/or flame, such as heat and/or flame from aircraft engine or rocket exhausts, as well as potentially to smoke and/or other chemical and/or biological agents, as from a threat from terrorists, a need has been ascertained, to which this invention is addressed, for a way to protect the air filter and the conduit against heat and/or flame.
This invention provides for use with and combines with a breathing mask of the type noted above, a protective cover for the conduit and for the canister. The protective cover comprises a fabric shell, which is adapted to cover the conduit and to cover the canister, except that the fabric shell has an air inlet or air inlets adapted to communicate with the air inlet or air inlets of the canister. The fabric shell is made from a heat-resistant, flame-resistant fabric. Preferably, the fabric shell is made from an aluminized fabric, such as an aluminized knit comprising approximately 33% polybenzimidazole fibers and approximately 67% polyparaphenylene terephthalamide fibers.
Preferably, the protective cover comprises a flame-resistant mesh, which adapted to be interposed between the air inlet or air inlets of the fabric shell and the air inlet or air inlets of the canister. Preferably, moreover, the flame-resistant mesh is made from polybenzimidazole fibers.
These and other objects, features, and advantages of this invention are evident from the following description of a preferred embodiment of this invention, with reference to the accompanying drawings.